This topic describes the metrics and their corresponding indicators supported by the monitoring data feature of ApsaraDB for MongoDB.

The following table describes the metrics supported by the monitoring data feature.
Note The supported metrics vary based on instance categories. The metrics displayed in the ApsaraDB for MongoDB console prevail.
Instance Metric Description
  • Standalone instances
  • Replica set instances
  • Sharded cluster instances
 CPU utilization cpu_usage: the CPU utilization of the instance.
Memory usage mem_usage: the memory usage of the instance.
IOPS usage The IOPS of the instance. The following items are included:
  • data_iops: the IOPS of the data disk.
  • log_iops: the IOPS of the disk that stores logs.
IOPS usage percentage The percentage of the IOPS used by the instance to the maximum IOPS allowed.
Disk usage The total disk space used by the instance. The following items are included:
  • ins_size: the total space used.
  • data_size: the disk space used by data files.
  • log_size: the disk space used by log files.
cursors The number of cursors used by the instance. The following items are included:
  • total_open: the number of cursors that are opened.
  • timed_out: the number of cursors that timed out.
Read/write queues The length of the queues that are waiting for global locks for the instance. The following items are included:
  • gl_cq_readers: the length of the queue that is waiting for global read locks.
  • gl_cq_writers: the length of the queue that is waiting for global write locks.
  • gl_cq_total: the length of the queue that is waiting for both global read and write locks.
WiredTiger The cache metrics of the WiredTiger engine used by the instance. The following items are included:
  • bytes_read_into_cache: the amount of data that is read into the cache.
  • bytes_written_from_cache: the amount of data that is written from the cache to the disk.
  • maximum_bytes_configured: the size of the maximum available disk space that is configured.
WiredTiger request queues The number of concurrent read and write requests that are being handled and the remaining number of concurrent read and write requests that can be handled. The following items are included:
  • write_concurrent_trans_out: the number of concurrent write requests that are being handled.
  • read_concurrent_trans_out: the number of concurrent read requests that are being handled.
  • write_concurrent_trans_available: the remaining number of concurrent write requests that can be handled.
  • read_concurrent_trans_available: the remaining number of concurrent read requests that can be handled.
Primary/secondary replication latency repl_lag: the latency in data synchronization between the primary and secondary nodes of the instance.
Number of requests sl_qps: the number of requests per second.
  • Standalone instances
  • Replica set instances that run MongoDB 4.0 or earlier
 I/O latency iocheck_cost: the latency of I/O operations, which indicates the I/O response performance.